<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="https://static.web.sdo.com/chuanshi/libs/common.css">
    <style>
        ul {
            display: flex;
            /* width: 500px; */
            /* height: 500px; */
            border: 2px solid red;
        }

        ul:nth-of-type(1) {
            flex-direction: row;
        }

        ul:nth-of-type(2) {
            flex-direction: column;
        }

        ul:nth-of-type(3) {
            flex-direction: row-reverse;
        }

        ul:nth-of-type(4) {
            flex-direction: column-reverse;
        }

        li {
            width: 50px;
            height: 50px;
            text-align: center;
            line-height: 50px;
            color: #fff;
            font-size: 2em;
            margin: 10px;
            background-color: brown;
        }
    </style>
</head>
<body>
    <h2>row</h2>
    <ul>
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li>4</li>
        <li>5</li>
    </ul>
    <h2>column</h2>
    <ul>
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li>4</li>
        <li>5</li>
    </ul>
    <h2>row-reverse</h2>
    <ul>
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li>4</li>
        <li>5</li>
    </ul>
    <h2>column-reverse</h2>
    <ul>
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li>4</li>
        <li>5</li>
    </ul>
</body>
</html>